dwest76

I've been having some problems with coolant coming out of the overflow reservoir on my 4Runner, it's an 87 22re recently rebuilt with all Engnbldr stuff. If you jump in the truck and drive, it will spew coolant (about a quart) ONE time, and then you could drive it all day. It does this everytime, and spews once. I've jumped in it cold and drove and I've let it warm up about 20 or 30 minutes before driving and it does it both ways. Never in the driveway, just when you drive after about 5 or 10 minutes.

Here's what I've done:

• new thermostat
• 1/16" hole in new thermostat
• new heater core
• flushed radiator with hose, didn't appear clogged (it's new)
• new radiator cap
• checked water pump, looks new
• fan clutch is good
• compression test perfect
• coolant sniff test-negative (no exhaust in coolant)
• mechanic re-did sniff test
• cylinder leak down test-no air in radiator
• no coolant in oil/oil in coolant

I may be leaving some things out, but that seems to be about it. I've got it at a local shop now, and the mechanic there is a little stumped too. Anybody got any ideas? The only thing I can think to try now is putting a bigger hole in the thermo, or buying the dual stage type. Could this be a hose leak somewhere drawing in air as the truck cools? I've never seen a leak anywhere on the ground, it only comes out the overflow. I've never had a coolant level issue, so something must have happened. This all started happening when the temperature got around 20 and less around here.

GettingNasty

sometimes thermestats get stuck.. maybe your head gasket is partialy blown... sorry for the spelling just woke up.. ugh keep me posted but it also could be a hairline crack in your block from the cold weather you didnt have the right mix of coolent and started it one morning with slush just a thought i really doubt it tho

PirateMcgee

I would try a new rad cap (your new one may be defective)

that's what caused it in my 4runner

you might try going to a 180 thermostat with no hole, I've had no surging issues and it's plenty hot still.

Did you bleed the system after installing everything?

dwest76

I tested the new thermostat out on the oven and it opened correctly for that. maybe the cold weather is causing it to stick?

I'm hoping it's not the head gasket since all the tests that I've done for that have shown it to be fine......is it possible that a leak is sealing itself up after the truck is driven? I've let it run in the driveway for an hour and everything has been fine.


I bled the system a couple of times, I was reasonably sure that the air was gone.

The radiator and cap are both fairly new, so I'm not convinced the original cap was bad but I replaced it anyway. So I would have had two bad caps which seems unlikely. If that is the case wouldn't it stay open? After it spews once it's been ok.


Keep'em comin, any other ideas?

dwest76

bump btt

mt_goat

The 22re has a strange coolant flow design that tends to cycle the t-stat when the heater is on, unless you use a dual stage t-stat. See 4crawlers write-up on that: http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

Also make sure that you've got all the air out of the system.

mt_goat

This really leads me to think you have an air pocket somewhere. Once the air pocket gets hot and expands it pops the pressure limit on the rad cap. I would think it would only happen once though, so maybe each time you cool down there is a new air packet forming or something. Make sure there is enough coolant in the overflow so the system can suck it back in during cool down. Also make sure the tube that sucks the coolant back in doesn't have any air leaks that would allow it to suck in air instead of coolant.

The head gasket could also be leaking exhaust gases into the cooling system a little bit during the warm-up. Gaskets can leak slightly during warm-up and then close up once the metal parts stop the thermal expansion process.

dwest76

I'm leaning towards your first idea that it's sucking air from somewhere. Are you talking about the tube from the overflow to the radiator? The motor is sucking back in coolant as it cools off, you can see the overflow level does go down, but maybe air is still getting mixed in there with it.

As far the HG goes, the only test that I did when cold was the compression test. The sniff test and cylinder leak down were both done when warm so the gasket could have sealed up then, I'll talk to the mechanic about the doing the cylinder leak down when cold, that should rule it out. He may have already tried that.

The frustrating thing about either of these is that I've let it warm up for 20 or 30 minutes in the driveway, running the rpms up and down periodically until it's good and warm, and then it will spew when I drive it. I would have thought that the HG would have been warm enough to seal at that point and any air pocket would have bubbled up in that warm-up time. HULK SMASH!!!

myyota

This may sound stupid, but check the overflow tank cap and make sure the over flow hose from the radiator to the cap is hooked up right. When i had my 84 4Runner it would do the same thing every time it was started, replaced the thermostat and that didn`t work, the radiator was good, so i started looking at the overflow tank and the hose from the radiator to the top of the overflow tank was hooked up backwards. Reversed the conections and all was good.

mt_goat

Yes I was. Good luck

Nogarage

myyota: That's really strange. Is there a check valve in the overflow hose going to the overflow tank? Why would reversing the connections affect the flow? Any idea?

dwest: So definitely check out the overflow hose hookup. but I'm curious, is it a stock radiator, or could you be overfilling a non-stock radiator that holds less than the stock? For instance, the system operates on about a quart less than the stock rad, so it expels the excess...? Just my 2 cents.

ibeamtaco

air in system bleed cooling system or t stat or cap i put new t stat eavry time i take hose off y not 5 dollors more

and air in system will cause a burp and than it will settle 4 a while before it hits again

mt_goat

Also check for pin hole leaks at top of rad.

dwest76

It is not a stock radiator so the capacity could be different. i checked this out by filling everything (burped and everything) and drove it. it spewed, I drove another 45 minutes and parked it. The next day the level in the overflow was down but not Low yet, and the radiator level also looked OK so I jumped in and drove. Spewed again. I did this twice so I'm looking more towards air in the system I think.

I haven't noticed anything on top of the radiator, but I'll look again. I really think it's something somewhat silly like that rather than a HG problem but I don't know how to check for that. Could a pressure test find something like this?

mt_goat

The radiator can't be overfilled, so that's a mute point. Now that I think about it, I've had pin hole leaks in the top of my radiator and it never spewed coolant so that's probably a mute point too.

I know you don't want to hear this, but I think I'd try running a test for exhaust gas in the coolant.

Did you use EBs special head bolt torquing proceedure when you torqued the head? Did you do a retorque after warm-up?

dwest76

You mean a test other than the sniff type test? I've run the test where you put the fluid tester in the radiator cap for a few minutes and the liquid turns color if you have exhaust gases. Always came out clean......

The PO did the rebuild, so I'm not sure. I've had the truck about a year and have put about 8-9k on it with no problems to speak of.

Believe me, at this point I don't care what the problem is, I just need to fix it.

mt_goat

Oh, that's good. I didn't see that, guess I should read better.

mt_goat

Have you tried a pressure test of the cooling system? If, not that would be my next step.

ibeamtaco

run the car with the heater on i bet there is air in heater hose the heater hose sits high on rear of engine making it hard to get air out so start truck with cap off heater on when you have hot air in vents and you get a burp you schould have all air out also if ur radiator sits 2 low it can cause this issue beacuse its trying 2 move water up 2 motor
other good thing to ck is make sure both hoses have pressure when cars at 190 temp and botom of radiator is cold

Zelephant

I just have a quick newbie question about this topic: I see a lot of suggestions to bleed the cooling system, but I thought the 22RE cooling system didn't need to be bled. I thought I saw that on this site somwhere. Which is true?